In general, a photolithography process includes the steps of: applying a photoresist composition on a substrate such as a wafer, a glass, a ceramic, a metal, or so on by a spin coating, a roller coating, or so on; forming a photoresist layer by heating and drying the applied photoresist composition; forming a photoresist pattern by exposing the photoresist layer to a exposure light of a predetermined pattern, optionally heating, and developing the exposed photoresist layer; and forming a semi-conductor circuit pattern by etching the substrate with the formed photoresist pattern as a mask. The photolithography process is widely used in production of a semi-conductor such as IC (Integrated Circuit), a substrate of a LCD (Liquid Crystal Display) panel, and so on.
Due to an increasing demand for a highly integrated semi-conductor device, KrF excimer laser of a wavelength of 248 nm and ArF excimer laser of a wavelength of 193 nm are used as a light source for the photolithography process. In addition, F2 excimer laser (157 nm), EUV (Extreme Ultra Violet), VUV (Vacuum Ultra Violet), E-beam, X-beam, ion beam, etc have been studied and developed as the light source for the lithography process. However, as the wavelength of the exposure light becomes shorter, during the light exposure process, an optical interference of the light reflected at the etching layer of the semi-conductor substrate increases. The interference of the light induces an undercutting, a notching, etc., and deteriorates the photoresist pattern profile and the thickness uniformity of the pattern. To overcome these problems, a bottom anti-reflective coating (BARC) layer is conventionally formed between the etching layer and the photoresist layer to absorb the exposure light. According to the material for forming the anti-reflected coating layer, the anti-reflective coating layer can be classified into an inorganic anti-reflective coating layer made of titanium, titanium dioxide, titanium nitride, chrome oxide, carbon, amorphous silicon, and so on, and an organic anti-reflective coating layer made of a polymer. In comparison with the inorganic layer, the organic anti-reflective coating layer does not generally require complex and expensive apparatus such as a vacuum deposition equipment, a chemical vapor deposition (CVD) device, a sputter device or so on for forming the layer, and has a high absorptivity for a radioactive light, and is generally insoluble in a photoresist solvent. Also, materials of the coating layer do not diffuse from the anti-reflective coating layer into a photoresist layer during coating, heating, and drying the photoresist layer, and the organic anti-reflective coating layer has an excellent etch rate in a dry etch process of a photolithography process. But until now, in the photolithography process using various radiation sources, including ArF excimer laser, the conventional composition for forming the organic anti-reflective coating layer is not satisfactory in its characteristics, such as an absorptivity of an exposure light, an etch rate, an adhesiveness to the substrate, and so on.